1. Field of the Invention
The present invention relates to a measurement system for a semiconductor manufacturing line and, more particularly, to a measurement system in which each apparatus for measuring a manufactured semiconductor device is integrated into a cluster such that conveyance of a unit of wafers for measurement of various parameters can be automatically accomplished with a robot.
2. Background of the Related Art
Generally, a semiconductor device is manufactured through a variety of procedural steps. That is, in a semiconductor manufacturing line, process apparatuses perform processes such as an oxidation process, a diffusion process, a photographic process, an etching process, and an ion injection process. In addition, a measurement system and an automatic control system are provided thereon.
All the process apparatuses for the above processes are constructed such that wafers, which have gone through the process in question, can be conveyed to a measurement system so that they can undergo checking to see if there are any defects in hardware or software. Wafers which are found to have no defects are conveyed so that they can go through subsequent processing. Wafers found to have defects are conveyed to be repaired or destroyed.
A wafer which has gone through one process may need to have various measurements taken. Thus, a plurality of measurement apparatuses for the various measurements must be set up in the same manufacturing line.
Most of the measurement apparatuses have simple hardware compared with the process apparatuses themselves. However, since many measurement apparatuses are required for each process apparatus, much space is required to accommodate the measurement apparatuses.
In recent years, a measurement apparatus for measuring a wafer having a size of above 200 mm has been developed using a robot in place of tweezers to convey wafers. However, the robot is generally large, and the space it occupies enlarges the overall volume of the measurement apparatus. Therefore, when a plurality of measurement apparatuses are installed for one process, it is difficult to make efficient use of the limited space in a manufacturing line.
In addition, since the conveying distance between the measurement apparatuses is increased by the enlarged volume of the measurement apparatus, much time is wasted transferring wafers from one process apparatus to another, and it becomes difficult to convey the wafers smoothly. Furthermore, when a wafer is conveyed from one measurement apparatus to another, the wafer can become contaminated by particles in the air.